Brussels: The European Union and Turkey agreed on a deal to stem the migrant crisis, including a three-billion-euro ($3.2-billion) aid package for Syrian refugees in Turkey, EU president Donald Tusk said after a summit in Brussels on Sunday.

"Our agreement sets out a clear plan for the timely re-establishment of order at our shared frontier. We will also step up our assistance to Syrian refugees in Turkey through a new refugee facility of three billion euros," Tusk told a press conference with Turkish Prime Minister Ahmet Davutoglu.

The EU also agreed to open a new chapter in Turkey's stalled bid for membership of the bloc in exchange for Turkey's cooperation in reducing the flow of refugees and migrants, Tusk said.

Visa requirements for Turkish citizens visiting the EU's passport-free Schengen area would also be relaxed by October 2016, he said.

Brussels would "monitor closely at least once a month" the progress being made by Turkey, Tusk added.